Study looks at effect of nitrogen loss on corn growth

Farmers have known for a long time about a big difference between corn growth patterns and nitrogen management in heavy clay soils and in sandy or silt loam soils, according to Josh Lofton, LSU AgCenter researcher at the Macon Ridge Research Station.

One of the latest research projects funded by the Louisiana Soybean and Grain Research and Promotion Board will look at the effect of nitrogen loss on corn growth.

His research project will look at how nitrogen loss affects growth rates and will also look at how growers can tell when they need to apply additional nitrogen after corn has been flooded.

The project has three treatments that will allow for a simulated flood that will cause a 24 hour period with no oxygen, he said.

One research plot will have early-season flooding before the plants reach the sixth true leaf stage. The second will be flooded midseason or at the late vegetative stage. And the third plot will not be saturated at all, but it will pond from time to time just from natural rain.

“What everybody knows and has thought and theorized is when you put the soil under water, you’re going to lose nitrogen,” he said.

Whether the loss is from leaching or denitrification, the grower needs to know when and if more nitrogen should be applied.

“What we’re thinking is when you get this flooding event real early in the season, you get such a decrease in your corn growth that it’s going down almost parallel to your nitrogen,” Lofton said.

“This is bad news for the grower because it means when you lose a little bit of nitrogen, you’ve already lost a little bit of corn growth,” he said.

Lofton said there is still a lot to learn about nitrogen loss and its effect on the crop: “This study is the beginning of a process.”

Lofton wants to answer the question of how much efficiency growers are getting from their corn crop in clay soil versus sandy loam soil.

“We’re hoping after about two years of data we can move from just data collection to starting to put in some management practices,” he said.

This is actually the first step in this process, he said. “There are still a lot of things that we need to know.”

He’s hoping the study will answer a number of these questions and give him hard numbers on the amount of corn lost as well as the amount of nitrogen lost.